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  • Inheritance in Java

    - by stevebot
    If I have an abstract class in java named Foo and it has an implementor named Bar then I want to know the following. lets say Foo looks something like public abstract class Foo { Service serviceFoo ... } And Bar is public class Bar extends Foo { ... } Also, lets assume I have an instance with Foo, named foo, currently that has serviceFoo instantiated If I then declare: Foo foo = new Bar(); will this create a a new instance of Bar that has serviceFoo instantiated or not? E.g. will that field be inherited and instantiated or just inherited?

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  • Painting to Form then to Printer

    - by jp2code
    I often find myself needing to create custom reports that do NOT work with Crystal Reports or Report Viewer. Often, I hack a DataTable together and dumping that into a DataGridView control. It is never pretty, and printing is difficult. What I need is a class that I can call using the OnPaint event, but I've never sat down and written all of the Pen and Brush commands until now. Painting to the screen and painting to a printer both use the Graphics object, so I want to build a class that I'd pass in the Graphics object, my window bounds (a Rectangle), and some data (in the form of an instance of my class) that I'd use to paint a form or a sheet of paper. That sounds like a great concept! Surely, someone has done something like this before. Does anyone know of a book, a website tutorial, or video that goes into this? If someone wants to write all that out for me here, more power to you - but I'd think that would be too much work.

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  • Alternative to c++ static virtual methods

    - by Jaime Pardos
    In C++ is not possible to declare a static virtual function, neither cast a non-static function to a C style function pointer. Now, I have a plain ol' C SDK that uses function pointers heavily. I have to fill a structure with several function pointers. I was planning to use an abstract class with a bunch of static pure virtual methods, and redefine them in derived classes and fill the structure with them. It wasn't until then that I realized that static virtual are not allowed in C++. Is there any good alternative? The best I can think of is defining some pure virtual methods GetFuncA(), GetFuncB(),... and some static members FuncA()/FuncB() in each derived class, which would be returned by the GetFuncX(). Then a function in the abstract class would call those functions to get the pointers and fill the structure.

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  • How to implement arrays in an interpreter?

    - by Ray
    I have managed to write several interpreters including Tokenizing Parsing, including more complicated expressions such as ((x+y)*z)/2 Building bytecode from syntax trees Actual bytecode execution What I didn't manage: Implementation of dictionaries/lists/arrays. I always got stuck with getting multiple values into one variable. My value structure (used for all values passed around, including variables) looks like this, for example: class Value { public: ValueType type; int integerValue; string stringValue; } Works fine with integers and strings, but how could I implement arrays? (From now on with array I mean arrays in my experimental language, not in C++) How can I fit the array concept into the Value class above? Is it possible? How should I make arrays able to be passed around just as you could pass around integers and strings in my language, using the class above? Accessing array elements or memory allocation wouldn't be the problem, I just don't know how to store them.

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  • Grails deploy on Tomcat6

    - by Jack
    Hello, while trying to deploy a Grails application into tomcat6 I ran into some problems: I used the grails war command to build up a war, then copied it to var/lib/tomcat6/webapps and tried to restart the container. I had to change default Tomcat policy to skip security exceptions, since I couldn't access environment variable (like grails.env), then tried again but it gives me an exception related to instantiating something, but it's not clear where should I try to fix the error, according to tomcat6 logs the problem is: SEVERE: Exception sending context initialized event to listener instance of class org.codehaus.groovy.grails.web.context.GrailsC$ org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'pluginManager' defined in ServletContext$ at java.lang.Thread.run(Thread.java:619) Caused by: org.codehaus.groovy.grails.exceptions.NewInstanceCreationException: Could not create a new instance of class [Hiberna$ ... 1 more Caused by: java.lang.NoClassDefFoundError: org.hibernate.cfg.Environment It seems like it's unable to load org.hibernate.cfg.Environment class. I checked the applicationContext.xml and it refers to grails.xml to search for plugins, in this last file I actually have HibernateGrailsPlugin. Where should I look to find if the plugin is present?

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  • Google App Engine python - Self is not defined

    - by sdasdas
    I have a request that maps to this class ChatMsg It takes in 3 get variables, username, roomname, and msg. But it fails on this last line here. class ChatMsg(webapp.RequestHandler): # this is line 239 def get(self): username = urllib.unquote(self.request.get('username')) roomname = urllib.unquote(self.request.get('roomname')) # this is line 242 When it tries to assign roomname, it tells me: <type 'exceptions.NameError'>: name 'self' is not defined Traceback (most recent call last): File "/base/data/home/apps/chatboxes/1.341998073649951735/chatroom.py", line 239, in <module> class ChatMsg(webapp.RequestHandler): File "/base/data/home/apps/chatboxes/1.341998073649951735/chatroom.py", line 242, in ChatMsg roomname = urllib.unquote(self.request.get('roomname')) what the hell is going on to make self not defined

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  • StructureMap: Wiring (generic) implementations to an implementation of another type

    - by Jeremy Frey
    If I have an interface: public interface IRepository<T> And an abstract class: public abstract class LinqToSqlRepository<T, TContext> : IRepository<T> where T : class where TContext : DataContext And a whole bunch of implementations of IRepository / LinqToSqlRepository (e.g. AccountRepository, ContactRepository, etc.), what's the best way to to use StructureMap (2.5.3) to generically wire them all up? e.g., I want this code to pass: [Test] public void ShouldWireUpAccountRepositories { var accountRepo = ObjectFactory.GetInstance<IRepository<Account>>(); Assert.IsInstanceOf<AccountRepository>(accountRepo); } Without explicitly writing this: ObjectFactory.Configure(x => x.ForRequestedType<IRepository<Account>>() .TheDefaultIsConcreteType<AccountRepository>()); In the past, we've always created a specific interface on each repository that inherited from the generic one, and used the default scanner to automatically wire all of those instances, but I'd like to be able to ask specifically for an IRepository<Account> without cluttering up the project with additional interfaces / configurations.

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  • Weird use of generics

    - by Karl Trumstedt
    After a bit of programming one of my classes used generics in a way I never seen before. I would like some opinions of this, if it's bad coding or not. abstract class Base<T> : where T : Base<T> { // omitted methods and properties. virtual void CopyTo(T instance) { /*code*/ } } class Derived : Base<Derived> { override void CopyTo(Derived instance) { base.CopyTo(instance); // copy remaining stuff here } } is this an OK use of generics or not? I'm mostly thinking about the constraint to "itself". I sometimes feel like generics can "explode" to other classes where I use the Base class.

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  • Problem about python import with error

    - by xiao
    Hello, I have write a small python module with one class and two functions. The skeleton of the module is as following: #file name: test_module.py class TestClass: @classmethod def method1(cls, param1): #to do something pass def __init__(self, param1): #to do something ... def fun1(*params): #to do something ... def fun2(*params): #to do something ... Another py file is a small script which imports function and class from the module, as following: import sys from test_module import TestClass, fun1, fun2 def main(sys_argv): li = range(5) inst1 = TestClass(li) fun1(inst1) fun2(inst1) return if __name__ == "__main__": main(sys.argv) But when I execute the script, it is broken with following message: ./script.py: line 4: syntax error near unexpected token `(' ./script.py: line 4: `def main(sys_argv):' I am not sure what the problem is. Is it a problem with import? But when I try to import the module in ipython, everything is just ok.

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  • Groovy: stub typed reference

    - by Don
    Hi, I have a Groovy class similar to class MyClass { Foo foo } Under certain circumstances I don't want to initialize foo and want to stub out all the calls to it. Any methods that return a value should do nothing. I could do it like this: Foo.metaClass.method1 = {param -> } Foo.metaClass.method2 = { -> } Foo.metaClass.method3 = {param1, param2 -> } While this will work, it has a couple of problems Tedious and long-winded, particularly if Foo has a lot of methods This will stub out calls to any instance of Foo (not just foo) Although Groovy provides a StubFor class, if I do this: this.foo = new groovy.mock.interceptor.StubFor(Foo) I get a ClassCastException at runtime. Although this would work if I could redefine foo as: def foo But for reasons I won't go into here, I can't do that. Thanks, Don

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  • Android alarm not working

    - by erdomester
    I've been struggling with this for hours. I've also checked the documentation and several topics. I found this code in two topics, both guys said the code was working perfectly, but not on my computer. The first Toast appears, but the second one never. What is wrong? public class HelloAndroid2 extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Intent intent = new Intent(this, AlarmReceiver.class); PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_ONE_SHOT); AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE); alarmManager.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (10 * 1000), pendingIntent); Toast.makeText(this, "Alarm set", Toast.LENGTH_LONG).show(); } public final class AlarmReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Toast.makeText(context, "Alarm worked.", Toast.LENGTH_LONG).show(); } } }

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  • Using Interfaces in an action signature of ASP.NET MVC controller

    - by Dmitry Borovsky
    Hello, I want to use interface in Action signature. So I've tried make own ModelBinder by deriving DefaultModelBinder: public class InterfaceBinder<T> : DefaultModelBinder where T: new() { protected override object CreateModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Type modelType) { return base.CreateModel(controllerContext, bindingContext, typeof(T)); } } public interface IFoo { string Data { get; set; } } public class Foo: IFoo /*other interfaces*/ { /* a lot of other methods and properties*/ public Bar Data{get;set;} string IFoo.Data { get{return Data.ToString()}; set{Data = new Bar(value)}; } } public class MegaController: Controller { public ActionResult Process([ModelBinder(typeof(InterfaceBinder<Foo>))]IFoo foo){/*bla-bla-bla*/} } But it doesn't work. Does anybody have idea how release this behaviour? And yes, I know that I can make my own implementation of IModelBinder, but I'm looking for easier way.

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  • assistance with classifying tests

    - by amateur
    I have a .net c# library that I have created that I am currently creating some unit tests for. I am at present writing unit tests for a cache provider class that I have created. Being new to writing unit tests I have 2 questions These being: My cache provider class is the abstraction layer to my distributed cache - AppFabric. So to test aspects of my cache provider class such as adding to appfabric cache, removing from cache etc involves communicating with appfabric. Therefore the tests to test for such, are they still categorised as unit tests or integration tests? The above methods I am testing due to interacting with appfabric, I would like to time such methods. If they take longer than a specified benchmark, the tests have failed. Again I ask the question, can this performance benchmark test be classifed as a unit test? The way I have my tests set up I want to include all unit tests together, integration tests together etc, therefore I ask these questions that I would appreciate input on.

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  • PLCameraController is not adding in viewcontroller

    - by sujyanarayan
    Hi, I've declared PLCameraContoller instance in my AppDelegate class as:- self.cameraController = [PLCameraController performSelector:@selector(sharedInstance)];[cameraController setDelegate:self]; And I'm accessing it in one of my viewcontroller class as:- del = [[UIApplication sharedApplication] delegate]; UIView previewView = [del.cameraController performSelector:@selector(previewView)]; previewView.frame = CGRectMake(0,0, 320, 480); self.view = previewView; [del.cameraController performSelector:@selector(startPreview)]; [del.cameraController performSelector:@selector(setCameraMode:) withObject:(NSNumber)1]; Where "del" is an instance of my AppDelegate class. But i can see only black background in my viewcontroller view in iphone device. Also if i remove "self" from the appdelegate.m code of cameracontroller it also showing blank. How can i get camera in my view controller? I'm pretty much struggling with it. Thanks in Adv.

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  • nHibernate query looking for the related object's related object

    - by code-zoop
    I have an nHibernate querie issue that looks quite straight forward, but I can't seem to get my head around it! I am creating some simple example classes to illustrate my problem: public class Car { public int Id { get; set; } public IList<Interior> InteriorParts { get; set; } } public class Interior { public int Id { get; set; } public InteriorProducer Producer { get; set; } } public class InteriorProducer { public int Id { get; set; } } Now to the query: I have the id of the InteriorProducer, but need to get a list of Cars where the interior have been produced by the interior producer. So in a simple, pseudo SQL, it looks something like this: select cars where car.InteriorParts.Producer.Id = Id I have a really hard time getting my head around this to create an nHibernate query. Any Ideas? Thanks

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  • Problem with mysql query to replace a string

    - by alex
    I've used mysql's update replace function before, but even though I think I'm following the same syntax, I can't get this to work. Here's what I'm trying to do: UPDATE contained_widgets SET preference_values = REPLACE(preference_values, '<li><a_href="/enewsletter"><span class="not-tc">eNewsletter</span></a></li>', '<li><a_href="/enewsletter"><span class="not-tc">eNewsletter</span></a></li> <li> <a_href="/projects"><span class="not-tc">Projects</span></a></li>'); Query OK, 0 rows affected (0.00 sec) Rows matched: 77 Changed: 0 Warnings: 0 I don't see what I'm missing. Any help is appreciated. I edited "a " to "a_" because the site thinks I'm posting spam links otherwise.

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  • PHP: prevent invocation of method X from from context != Y

    - by sunwukung
    This is a tricky one. I am "emulating" ZF Bootstrapping (surface appearance). Don't ask me why, call it academic interest. So I have a Bootstrap Abstract with a method "run" that iterates over itself to locate any methods prefixed with "init". The application looks for a user defined class which extends this class, in which the user can define any number of methods in this way. However, I want to prevent the user from being able to execute the "run" command of it's parent class, while still exposing the same command for the client code. Anyone got any thoughts/advice/guidance? regards SWK

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  • HQL join after output of subquery

    - by user350374
    Hey, Say I have 3 classes class foo1 { List prop1;} class foo2 { foo3 prop2;} class foo3{ int Id;} now I want to select distinct foo2's from foo1 and get Id of foo3. I need to write a HQL stmt for the same. I tried the following select c.Id from (select distinct(a.prop1) from foo1.prop1 as a ) as b inner join b.prop2 as c This throws an 'Antlr.Runtime.NoViableAltException How do you suggest I should go about the same. Please note the inner subquery is working fine. So if I have made some mistakes in there please ignore that. I need a method to do the latter. Thanks in Advance.

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  • Get pointer to member function from within member function in C++

    - by Eli
    Currently in the program I am attempting to write I need to be able to get a pointer to a member function within a member function of the same class. The pointer needs to be passed to a function as a void (*)(). Example: //CallFunc takes a void (*)() argument class testClass { public: void aFunc2; void aFunc1; } void testClass:aFunc2(){ callFunc(this.*aFunc1); // How should this be done? } void testClass:aFunc1(){ int someVariable = 1; } I'm trying to do this in GCC 4.0.1. Also, the member function being called can't be static because it references non-static variables in the class that it is part of.

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  • Ruby on Rails: attr_accessor for submodels

    - by williamjones
    I'm working with some models where a lot of a given model's key attributes are actually stored in a submodel. Example: class WikiArticle has_many :revisions has_one :current_revision, :class_name => "Revision", :order => "created_at DESC" end class Revision has_one :wiki_article end The Revision class has a ton of database fields, and the WikiArticle has very few. However, I often have to access a Revision's fields from the context of a WikiArticle. The most important case of this is probably on creating an article. I've been doing that with lots of methods that look like this, one for each field: def description if @description @description elsif current_revision current_revision.description else "" end end def description=(string) @description = string end And then on my save, I save @description into a new revision. This whole thing reminds me a lot of attr_accessor, only it doesn't seem like I can get attr_accessor to do what I need. How can I define an attr_submodel_accessor such that I could just give field names and have it automatically create all those methods the way attr_accessor does?

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  • Problem with Classes in Python..

    - by Gui
    Ok guys, I'm really new at python (and programming itself) so sorry for my ignorance, but I really needed to ask this. So im doing a wxPython project where I added several tabs for a notebook (each tab of the notebook = a class) and there is one tab where I added a checkbox (in a tab, lets call it for example Tab1), and what I want is that when someone checks it, a button that exists in other tab (class called for example tab2) gets hidden where previously it was being shown. Well I see that it isn't hard to accomplish this, but my problem is the classes (tab1 and tab2, in this example). I've been trying to figure it out by searching but I guess im not searching hard enough because I just can't get it right. If they were in the same class I wouldn't have a problem, but as they are in different classes, im having a huge struggle with this. Hope someone can help me, and sorry for my ignorance once again.

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  • Question about [Pure] methods

    - by devoured elysium
    Is the following method Pure? I'd say so, as it doesn't change in anyway the current class, thus, everything we can now currenly "see" in the class, before running this method will still be exactly the same after. Am I correct? class Set { ... public ISet<T> UnionWith(ISet<T> set) { ISet<T> unionSet = ... foreach (Element element in this) { unionSet.Add(element); } foreach (Element element in set) { unionSet.Add(element); } return unionSet; } }

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  • "partial views" best practices for 'container' divs?

    - by ropstah
    What is the 'best' way to handle the html markup for partial views? (which are also refreshed using AJAX) The biggest issue I run into is where to place the 'container' div... Consider having a masterpage and a partial view. (class="" could be interchanged with id="" depending if the partial is guaranteed to be unique, however this isn't really important to the issue i think) Masterpage: <div id="place1" class="placeholder"> <!-- render partial --> </div> Partial: <div id="partial1" class="partial"> <!-- content --> </div> I feel that something isn't being done right. However I cannot remove the div in the masterpage, because I need that to 'encapsulate' the response from AJAX partial updates. And also I cannot move the div in the partial to the masterpage, because that would require to move 'partial' info to the masterpage... How do you handle this?

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  • How do I let main thread suspend and wait for the System.Timer.Timer running

    - by Kelvin
    Hi I am using System.Timer.Timer I always get NULL after running my programme and it only works if I add this.sleep(6000). Suppose the reason is the main thread ends but the timer hasn't finished ... Here is the class and I call the class from my main form. Class class1 { string finalResult = ""; public string getNumber() { RunTimer(); return finalResult; } pubic void RunTimer () { timer = new System.Timers.Timer(30000); timer.Interval = 1000; timer.Elapsed += new System.Timers.ElapsedEventHandler(cal); timer.Start(); } private void cal(object sender,System.Timers.ElapsedEventArgs e) { finalResult += READFROMCOMPORT; } }

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  • strategy for observer pattern?

    - by fayer
    I want to use observer pattern for a logging system. We have got logObservers and logObservables. The class that will have to log something will implement iLogObservable and include these methods: private $logObservers = array(); public function addLogObserver($logObserver) { $this->logObservers[] = $logObserver; } public function removeLogObserver($logObserver) { $this->logObservers[] = $logObserver; } public function write($type, $message) { foreach($this->logObservers as $logObserver) { $logObserver->log($level, $message); ; } } Then I noticed, that a lot of classes that will use logging will have these methods and I have to copy paste. So isn't it better to have these methods in a class I call LogObservable or just Log and then use strategy (instantiate this class inside all classes that will have to log). When I change the methods in Log, all logObservables will be affected. However, I have not seen anyone use observer pattern with strategy pattern yet, but it seems to be very efficient and remove the duplications. What do you think?

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